The invention relates to injection molding of polymerizable material to form prosthetic teeth of polymeric material consisting of several layers.
Dehoff et al, the disclosure of which is incorporated herein by reference in its entirety, disclose prosthetic teeth. Roemer, et al. in U.S. Pat. No. 4,396,476 ,and U.S. patent application Ser. No. 09/333,727 filed Jun. 15, 1999 the disclosures of which are incorporated herein by reference in their entirety, disclose polymerizable tooth making compositions. Kura et al in U.S. Pat. No. 5,989,031, the disclosure of which is incorporated herein by reference in its entirety, disclose injection molding of thermoplastic to form a tooth. According to DIN 13914, artificial teeth for producing dental prostheses must consist of several layers because of the desired similarity to natural teeth. Such multilayer teeth have previously been produced exclusively by a pressing process, wherein the differently dyed pressing masses are placed by hand in the pressing tool. The pressing of the teeth is very labor-intensive. The distribution of the layers put in place by hand is subject to irregularities. The excess amounts necessary for pressing lead to considerable burr formation at the separating plane of the mold halves. This makes subsequent processing necessary. Thus considerable production effort is connected to the production of conventional multilevel teeth, so that these teeth are relatively expensive.
The present invention is based on the problem of creating an artificial tooth constructed of several layers whose production can be largely automated and in which a reproducible arrangement of layers is guaranteed and, in particular, burr formation is also minimized, so that low production costs result.
The invention provides multiple part dental tooth molds and prosthetic teeth with an enamel layer having zones of uniform thickness. Prosthetic teeth in accordance with a preferred embodiment of the invention are readily articulable within sets and proportionally consistent within families. Prosthetic teeth in accordance with the invention are useful for making full and/or partial dentures, and as crowns, implant teeth and shade guides having prosthetic teeth thereon.
Tooth molds are used in the dental industry for the manufacture of artificial teeth. Refining steps include a final finish-polish step, which provides a mold of high-definition of the surface properties of the artificial tooth to be produced by molding tooth making material therein.
Dehoff et al in U.S. Pat. No. 5,452,219 (Case 1619) discloses a method for making a tooth mold. Erdle in Australia 124,083 disclose ceramic articles and material and method for coloring or shading the same. Saffir in U.S. Pat. No. 2,380,568 disclose artificial tooth. Kelly in U.S. Pat. No. 2,514,075 disclose artificial tooth. Erdle in U.S. Pat. No. 2,517,100 disclose method of forming ceramic articles and producing different colors or shades along different potions of the article. Budish in U.S. Pat. No. 2,643,455 disclose artificial teeth. Rydin in U.S. Pat. No. 2,677,150 disclose method in producing artificial teeth. Slack, Jr. in U.S. Pat. No. 2,678,470 disclose polymerizing method. Saffir in U.S. Pat. No. 3,126,429 disclose method of casting teeth having different colored layers. Connan in U.S. Pat. No. 3,218,711 disclose artificial teeth. Swinson in U.S. Pat. No. 3,861,044 teaches a method of fitting a tooth with a dental inlay. Heitlinger et al. in U.S. Pat. No. 4,324,546 disclose an apparatus and method for the manufacture of dentures. Tanaka in U.S. Pat. No. 4,392,829 disclose metal porcelain dental restoration and method of making. Faunce in U.S. Pat. No. 4,433,959 disclose composite laminate dental veneer containing color systems. White in U.S. Pat. No. 4,436,684 describes methods of making three dimension models and mold cavities of internal body structure.
Tanaka in U.S. Pat. No. 4,481,227 disclose method of coloring bakable porcelain dental restorations. Moermann et al. in U.S. Pat. No. 4,575,805 disclose a method and a apparatus for the fabrication of custom-shaped implants.
Duret et al. in U.S. Pat. No. 4,611,288 describe a system for taking an impression of a body region for the production of a prosthesis.
Moermann et al. in U.S. Pat. No. 4,615,678 teach a blank from which an implant can be machined by an apparatus of the type disclosed in U.S. Pat. No. 4,575,805. Miller in U.S. Pat. No. 4,617,159 disclose method of molding a dental shade sample. Amdur et al. in U.S. Pat. No. 4,645,454 disclose porcelain products and methods. Blair et al. in U.S. Pat. No. 4,650,418 disclose dental restoration shading. Duret et al. in U.S. Pat. Nos. 4,663,720 and 4,742,464 disclose a method of making a dental prosthesis. Watanabe et al. in U.S. Pat. No. 4,681,633 disclose high strength calcium phosphate glass ceramic materials. Corbett in U.S. Pat. No. 4,722,689 disclose coated temporary dental crowns. Brandestini et al. in U.S. Pat. No. 4,766,704 describe a method and apparatus for machining a custom-shaped dental restorative part from a blank of dental material in a single operation. Brandestini et al. in U.S. Pat. No. 4,837,732 teach a method of facilitating acquisition of data defining the three-dimensional shape of prepared teeth and their immediate vicinity.
Rotsaert in U.S. Pat. No. 4,970,032 disclose processes for the manufacture of artificial teeth and crowns. Grossman et al. in U.S. Pat. No. 5,089,306 disclose glazing dental constructs. Hasegawa et al. in U.S. Pat. No. 5,127,834 disclose artificial teeth and method for making them. Rotsaert in U.S. Pat. No. 5,151,044 disclose blanks for the manufacture of artificial teeth and crowns. Emmons in U.S. Pat. No. 5,308,243 disclose method and compositions for producing life-like dental porcelain restorations and dental porcelain restorations so produced. Oden in U.S. Pat. No. 5,342,201 disclose method of manufacturing ceramic artificial tooth restorations.
It is an object of the invention to provide artificial teeth with an enamel layer having zones of constant thickness.
It is an object of the invention to provide a family of prosthetic teeth, including a first tooth in a first set of teeth having a first overall labial length, and a first back length, and a second tooth in a second set of teeth having a second overall labial length, and a second back length, wherein the ratio of the first to the second overall labial length is substantially equal to the ratio of the first to the second back length.
It is an object of the invention to provide a prosthetic tooth including a tooth body having two generally symmetrical curved grooves between three curved ridges on the labial face of the body at the incisal end of the body, wherein the grooves are deepest at the incisal end and extend substantially from the incisal edge to at least about 15 percent of the overall tooth length.
It is an object of the invention to provide an image of at least a portion of at least one upper tooth and at least one lower tooth, each said tooth being from the same side of the same set of teeth, modifying initial data corresponding to the image to form modified data, molding modified prosthetic teeth in molds made using the modified data, whereby, during articulation the modified prosthetic teeth contact along a larger proportion of tooth surface than prosthetic teeth made in molds using the initial data.
Set of teeth as used herein refers to teeth to be used for the same individual, such as is a single denture whether full or partial.
Family of teeth as used herein refers to sets of teeth of different sizes and/or shades but having common shapes.
A process for producing an artificial tooth comprising: injection molding polymerizable material into a mold to form an outer external polymeric layer. Then injection molding polymerizable material into the mold to form an inner polymeric layer applied on the first external layer. Then injection molding polymerizable material into the mold to form a solid core applied on the inner external layer.
The problems of high mold pressure and limited tooth shading are solved according to the invention in that low pressure is use for injection and shading may be custom blended at the molding site.
The invention relies upon the recognition that a considerable savings in cost can be achieved by injection molding technology, since injection molding is done completely automatically and hence a reproducible arrangement of layers can be guaranteed. This may involve a multicomponent injection molding process, wherein the material components form layers inside the tooth body so that, by dying the individual material components differently the natural tooth appearance can be optimally approximated.
A prosthetic tooth having an enamel layer which has a zone of substantially constant thickness. This tooth is molded using a dental tooth mold part prepared by imaging a dental pattern of a prosthetic tooth shade layer and/or shader mold part outer surface, and forming the dental pattern in a mold by program directed milling.
The invention provides a family of prosthetic teeth, including a first tooth in a first set of teeth has a first overall labial length, and a first back length, and a second tooth in a second set of teeth has a second overall labial length, and a second back length. The ratio of the first overall labial length to the second overall labial length is substantially equal to the ratio of the first back length to the second back length. Preferably the first tooth has a first shade length and the second tooth has a second shade length and the ratio of the first shade length to the first overall labial length is substantially equal to the ratio of the second shade length to the second overall labial length.
The invention provides a prosthetic tooth including a tooth body having two generally symmetrical curved grooves between three curved ridges on the labial face of the body at the incisal end of the body. The grooves are deepest at the incisal end and extend substantially from the incisal edge to at least about 15 percent of the overall tooth length.
The invention provides a method of making readily articulable prosthetic teeth by displaying an image of at least a portion of at least one upper tooth and at least one lower tooth from the same side of the same set of teeth, then modifying initial data corresponding to the image to form modified data, molding readily articulable prosthetic teeth in molds made using the modified data, whereby, during articulation the readily articulable prosthetic teeth contact along a larger proportion of tooth surface than prosthetic teeth made in molds using the initial data.